1. Field
The present disclosure relates generally to imaging systems and in particular to a method and apparatus for non-destructive examination of structures. Still more particularly, the present disclosure relates to a method and apparatus for identifying anomalies in a structure using a flexible large array organic photodetector.
2. Background
Non-destructive examination involves testing an object without destroying and/or damaging the object. Non-destructive examination may be used in the construction and the maintenance of all types of structures. Non-destructive examination may be employed to identify anomalies in structures such as, for example, without limitation, buildings, dams, aircraft, walls, submarines, wire ropes in suspension bridges, pressure vessels, pipes in industrial plants, underground pipelines, and other suitable structures. This type of testing may be used to identify additional anomalies such as cracking, corrosion, or other anomalies within or on a structure.
Non-destructive examination may be performed using a member of different types of test equipment. For example, ultra-sound systems and x-ray systems may be used to perform non-destructive examination of objects.
With an x-ray system, electromagnetic radiation may be used to produce an image of a structure. This type of image is usually produced to visualize regions below the surface of the structure. An x-ray system may include, for example, an x-ray source, an x-ray detection system, and a positioning system to align the x-ray source and x-ray detection system.
With currently used x-ray systems, the detectors may result in images that contain distortion. For example, a digital silicon based detector is typically flat in configuration. If the structure being tested has a non flat surface, portions of the image can become distorted. Poor detector contact to the part surface under examination will increase geometric unsharpness also referred to as blur, unwanted magnification and image distraction. These changes can be described by equation: MF=SID/SOD, where Source to object distance is (SOD) and source to image receptor distance is (SID).
The distance between portions of the x-ray detector and curved surfaces may change because the detector does not have a shape that is conformable or fitted to the curved surface.
The geometric unsharpness, image distortion, and unwanted magnification of an x-ray image is at the minimum found at the location where the detector is closest to parallel to the part and perpendicular to the x-rays. For example, if the flat detector is used with a pipe, geometric unsharpness in the image is located at the least along a line that goes through the center of the pipe that is perpendicular to the detector. The curvature of the pipe and the flat surface of the x-ray detector are not well-matched.
Therefore, it would be advantageous to have a method and apparatus that overcomes the problems described above.